KR100393340B1 - 4-cycle engine - Google Patents

Abstract

An oil tank 40 is attached to one side of the engine main body 1, and the oil tank 40 has a four-cycle engine in which an oil slinger for dispersing storage oil O and generating oil spray for lubrication is contained. A timing transmission case 36 is sandwiched between the engine body 1 and the oil tank 40, and the case 36 is used to transfer the engine body 1 from the engine body 1 to the oil tank 40. Shut off heat transfer. In this way, it is possible to arrange the oil tank away from the engine body without causing the engine to be enlarged, and to suppress the heat transfer from the engine body to the oil tank as much as possible, thereby preventing overheating of the oil in the oil tank. have.

Description

4-cycle engine {4-CYCLE ENGINE}

The present invention relates to a four-cycle engine in which an oil tank is attached to one side of an engine body, and the oil tank accommodates an oil slinger that scatters storage oil and generates oil spray for lubrication.

Such a four-cycle engine is already known, for example, as disclosed in Japanese Patent Laid-Open No. 9-170471.

In the conventional four-cycle engine, the oil tank is integrally formed on one side of the engine body as disclosed in the above publication.

However, this conventional invention has a difficulty in that the storage oil in the oil tank is easily overheated by the heat generated by the engine body.

The present invention has been made in view of such circumstances, and it is possible to arrange the oil tank away from the engine main body without causing the engine to be enlarged, and to suppress the heat conduction from the engine main body to the oil tank to the maximum. It is an object of the present invention to provide the four-cycle engine.

1 is a perspective view showing an example of use of the hand-held four-cycle engine according to the first embodiment of the present invention.

2 is a longitudinal sectional side view of the four cycle engine.

3 is an enlarged view illustrating main parts of FIG. 2;

4 is an enlarged longitudinal sectional view of the camshaft circumference of FIG. 3;

5 is a cross-sectional view taken along line 5-5 of FIG. 3.

6 is a sectional view taken along line 6-6 of FIG.

7 is a cross-sectional view taken along line 7-7 of FIG. 6.

8 is a cross-sectional view taken along line 8-8 of FIG. 6.

9 is a front view of a rod-shaped seal member.

FIG. 10 is a view from the arrow direction of FIG. 9;

11 is an enlarged view illustrating main parts of FIG. 5;

12 is a cross-sectional view taken along the 12-12 line of FIG. 3.

FIG. 13 is a sectional view taken along the 13-13 line of FIG. 12;

14 is a sectional view taken along line 14-14 of FIG.

15 is a sectional view taken along line 15-15 of FIG. 14;

16 is a bottom view of the head cover.

17 is a lubrication system diagram of an engine.

FIG. 18 is an explanatory view of an operation for sucking up oil in a cylinder head in various driver postures of an engine; FIG.

FIG. 19 is a cross-sectional view corresponding to FIG. 3 showing a second embodiment of the present invention; FIG.

20 is a view from the arrow direction in FIG. 19;

In order to achieve the above object, the present invention is attached to an oil tank on one side of the engine body, the oil tank engine body in a four-cycle engine containing an oil slinger to disperse the storage oil to generate oil spray for lubrication, And a timing transmission case which accommodates a timing transmission device for connecting a crankshaft and a camshaft supported by the engine body between the oil tank and the oil tank.

According to this first feature, heat conduction from the engine body to the oil tank is interrupted by the timing transmission case, thereby preventing overheating of the storage oil in the oil tank. In addition, since the timing transmission case is indispensable for an OHC engine, there is no fear of causing an enlargement of the engine.

In addition, the present invention, in addition to the above-mentioned features, a case cover is coupled to the timing transmission case surrounding the outer surface of the timing transmission device, and the oil tank is connected to and installed on the case cover so as to share a side wall. It is done.

According to this second feature, the case cover and the oil tank can be integrated, and the structure can be simplified, contributing to cost reduction.

In addition, the present invention, in addition to the first or second features, to form a bowl-shaped portion recessed in the tank inner side around the crankshaft on the outer wall of the oil tank, the oil to follow the convex curved surface of the bowl-shaped portion The third feature is one in which a slinger is formed.

According to this third feature, the dead space of the oil tank can be reduced by forming the bowl-shaped portion on the outer wall of the oil tank, and in addition, even in the rotational position of the engine in which the bowl-shaped portion is faced downward. The oil present around the bowl can be efficiently stirred and scattered by an oil slinger. Therefore, the oil slinger can be efficiently produced while reducing the amount of invalid storage of oil in the oil tank.

Furthermore, in addition to the third aspect, the present invention further includes a recoil starter disposed adjacent to the outside of the oil tank, and a driven member driven by the recoil starter is attached to the outer end of the crankshaft passing through the bowl shape. The thing fixed in the bowl shape is set as the 4th characteristic.

According to this fourth feature, the space in the bowl-shaped portion is effectively used for the arrangement of the driven member, and at the same time, the proximity of the recoil starter to the oil tank can be made, which can contribute to the miniaturization of the entire engine.

In addition to the first feature, the present invention provides a train for inducing cooling wind from a cooling fan attached to the crankshaft while executing a heat shield between the engine body and a carburetor connected to the engine body. The fifth feature is that the step-and-wind guide plate is arranged and installed, and the heat shield and wind guide plate are integrally connected to the timing transmission case, and the timing transmission case and the heat-dissipation-wind guide plate are configured as one part.

According to the fifth feature, since the heat shield and the wind guide plate are integrated with the timing transmission case fixed to the engine main body and become a single part, the heat shield and the wind guide plate are supported by the timing transmission case. The bolts that fix the wind guide itself to the engine body can be omitted or the number of bolts used can be greatly reduced. Therefore, the timing transmission case and the heat shield and the wind guide plate are integrated, and the number of parts and the number of assembly steps can be reduced, and the cost can be reduced.

In addition to the fifth aspect, the present invention is characterized in that the timing transmission case is provided with an oil transfer conduit and an oil return conduit receiving oil spray between the oil tank and the lubrication target portion in the engine body.

According to this sixth feature, the integration of the timing transmission case, the oil transfer conduit and the oil return conduit can further reduce the number of parts and the number of assembly steps, and can greatly contribute to the cost reduction.

The above and other objects, features and advantages in the present invention will become apparent from the description of the preferred embodiments described below in accordance with the accompanying drawings.

[Compatible Example]

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention.

First, the description starts from the description of the first embodiment of the present invention shown in Figs. As shown in FIG. 1, the handheld four-cycle engine E is attached to the drive part as a power source of the power trimmer T, for example. Since the power trimmer T is used for the cutter C in various directions depending on the working state, the engine E also inclines or reverses each time, and the driving posture is not constant.

First, the overall configuration of the handheld four-cycle engine E will be described with reference to Figs.

As shown in Fig. 2, Fig. 3 and Fig. 5, a carburetor 2 and an exhaust muffler 3 are attached to the engine body 1 of the handheld four-cycle engine E before and after, respectively. An air cleaner 4 is attached to the intake air inlet of the vaporizer 2. A fuel tank 5 made of synthetic resin is attached to the lower surface of the engine body 1.

The engine body 1 includes a crankcase 6 having a crank chamber 6a, a cylinder block 7 having one cylinder bore 7a, a combustion chamber 8a and an intake / exhaust opening in the combustion chamber 8a. A cylinder head 8 with ports 9 and 10, the cylinder block 7 and the cylinder head 8 being integrally cast and separately cast from the bottom of the cylinder block 7; The crankcase 6 is joined by bolts. The crankcase 6 is composed of first and second case halves 6L and 6R, which are divided left and right at the center thereof, and the two case halves 6L and 6R are bolted to each other. Are bonded. A plurality of cooling fins 38 are formed on the outer circumferences of the cylinder block 7 and the cylinder head 8.

The crankshaft 13 accommodated in the crank chamber 6a is supported by the cylinder bore 7a while being freely supported for rotation through the ball bearings 14 and 14 'at the first and second case bodies 6L and 6R. The piston 15 which is fitted and fitted is continuously contacted via a connecting rod 16. In addition, oil seals 17 and 17 'are attached to the first and second case halves 6L and 6R adjacent to the outer circumferential surface of the crankshaft 13 adjacent to the bearings 14 and 14'.

As shown in FIGS. 3 and 6 to 8, a gasket 85 is fitted between the cylinder block 7 and the joining surfaces of the first and second case halves 6L and 6R. In addition, between the first and second case half bodies 6L and 6R, a rod-shaped sealing member 86 is sandwiched and mounted as follows. That is, on one side of the joining surfaces of the first and second case bodies 6L and 6R, a U-shaped seal groove 87 is formed along the inner peripheral surface thereof, and the cylinder block 7 of the seal groove 87 is formed. At each end of the side), enlarged recesses 87a are continuously provided along the joining surfaces of the both case halves 6L and 6R. On the other hand, since the seal member 86 is made of an elastic material such as rubber, the rod-shaped portion has a circular cross section, but at both ends thereof, an enlarged end portion 86a of a rectangular cross section protruding at right angles from both sides is formed. The seal member 86 is bent into a U-shape with a rod-shaped portion to be fitted into the seal groove 87, and each enlarged end portion 86a is filled in the enlarged recess portion 87a. In this case, forming a pair of small projections 88 elastically in contact with the outer peripheral surface of the middle portion of the rod-shaped portion on the inner surface of the middle portion of the seal groove 87 is performed in the seal groove 87 of the middle portion of the seal member 86. Effective for preventing injury.

When the first and second case halves 6L and 6R are joined to each other, the rod-shaped portion of the seal member 86 and the outer surface of the enlarged end portion 86a are in close contact with the opposing joining surfaces, and both When the cylinder block 7 is joined to the upper surfaces of the case halves 6L and 6R by sandwiching the gasket 85, the upper surface of each enlarged end portion 86a is in close contact with the gasket 85. In this way, the joint surface which alternates | crosses both case half 6L, 6R and the cylinder block 7 in T shape is sealed according to one sealing member 86 and one gasket 85. As shown in FIG. In particular, by fitting each pair of enlarged end portions 86a and enlarged recesses 87a, the entire sealing member 86 can be accurately held in position without requiring any special skill. In addition, the fastening material of the rod-shaped portion and the enlarged end portion 86a of the seal member 86 is determined according to the depths of the seal groove 87 and the enlarged recess portion 87a for receiving it, Since there is little influence on the disturbance, it is possible to improve the assemblability of the engine main body 1 and ensure the sealing of the intersecting joint surfaces.

4 and 5, in the cylinder head 8, an intake valve 18 and an exhaust valve 19 for opening and closing the intake port 9 and the exhaust port 10, respectively, of the cylinder bore 7a. It is provided in parallel with the axis line, and before the ignition 20 is attached to the electrode close to the center of the combustion chamber 8a.

The intake valve 18 and the exhaust valve 19 exert a force in a valve direction closed by the valve springs 22 and 23 in the actuating valve cam chamber 21 formed in the cylinder head 8. Further, in the actuating valve cam chamber 21, rocker arms 24 and 25 in which the head of the intake valve 18 and the exhaust valve 19 are freely supported on the shaft by the cylinder head 8 are supported. Are superimposed, the camshaft 26 which opens and closes the intake valve 18 and the exhaust valve 19 via these rocker arms 24 and 25 becomes parallel with the crankshaft 13, and the actuating valve cam chamber 21 is carried out. Rotation is freely supported via ball bearings 27 and 27 'on the left and right side walls of the vehicle. One side wall of the actuating valve cam chamber 21 on which the ball bearing 27 is mounted is integrally formed with the cylinder head 8, and the one side wall of the cam shaft 26 is adjacent to the outer side of the bearing 27. An oil seal 28 is attached to the outer circumferential surface. The other side wall of the actuating valve cam chamber 21 is provided with an insertion port 29 for allowing the cam shaft 26 to be inserted into the cam chamber 21. After insertion of the cam shaft 26, the insertion port 29 is closed. The other side ball bearing 27 'is mounted on the bearing cap 30. The bearing cap 30 is fitted to the insertion hole 29 via the seal member 31, and is bolted to the cylinder head 8.

As shown in FIG. 4, FIG. 11, and FIG. 16, the head cover 71 which covers the open surface of the operation valve cam chamber 21 is joined to the upper end surface of the cylinder head 8. As shown in FIG.

The upper end surface 11 of the cylinder head 8 is connected to both ends of the inclined surface 11c and the inclined surface 11c so as to be lowered from the camshaft 26 toward the rocking points of the rocker arms 24 and 25, and is connected to each other. It consists of a pair of flat surfaces 11a and 11b having a height difference and parallel, and the head cover 71 has a flange portion 71a superimposed on such an upper end surface 11 of the cylinder head 8, and an actuating valve. A fitting wall portion 71b fitted to the inner circumferential surface of the cam chamber 21 is formed. A ring-shaped seal groove 90 is provided on the outer circumferential surface of the fitting wall portion 71b, and a zero ring 72 serving as a seal member close to the inner circumferential surface of the operation valve cam chamber 21 is attached thereto. The flange portion 71a is fixedly mounted to the cylinder head 8 by a pair of bolts 91 and 91 parallel to portions corresponding to the pair of flat surfaces 11a and 11b.

In this manner, when the fitting wall portion 71b of the head cover 71 is inserted into the inner circumferential surface of the actuating valve cam chamber 21 via the O-ring 72, the zero ring 72 is irrespective of the axial force of the bolt 91. A uniform fastening material can be provided to each part of the c), and a good seal state between the cylinder head 8 and the head cover 71 can be secured. In addition, the bolt 91 for fixing the flange portion 71a of the head cover 71 to the cylinder head 8 without the fastening material of the 0 ring 72 is fixed to the cylinder head 8. Only one thing can be used, and the number of uses can be greatly reduced. In particular, the flange portion 71a of the head cover 71 is fixedly mounted to the cylinder head 8 along a pair of bolts 91 and 91 parallel to the portions corresponding to the pair of flat portions 11a and 11b. As a result, the head cover 71 can be fixedly and securely mounted with a minimum bolt.

The camshaft 26 projects one end part to the outer side of the seal head 8 from the side where the said oil seal 28 is located. In the same way, the crankshaft 13 also protrudes one end portion outward of the crankcase 6, and a toothed driving pulley 32 is fixedly mounted at one end thereof, and teeth having twice the number of teeth than this. This driven pulley 33 is fixedly mounted to one end of the camshaft 26. The timing belt 34 with teeth is wound around both pulleys 32 and 33, and the crankshaft 13 can be driven with a reduction ratio of 1/2 of the camshaft 26. As shown in FIG. An actuating valve mechanism 53 is formed by the camshaft 26 and the timing transmission device 35.

In this way, the engine E is comprised of OHC type | mold, and the timing transmission apparatus 35 becomes a dry type arrange | positioned outside the engine main body 1. As shown in FIG.

As shown in FIGS. 3 and 12, a timing transmission case 36 made of synthetic resin, which is fixed to the engine body 1 with a bolt 37, is disposed between the engine body 1 and the timing transmission device 35. Therefore, the influence of the engine body 1 radiant heat on the timing transmission device 35 can be avoided.

In the engine body 1, an oil tank 40 made of synthetic resin, which is arranged to cover a part of the outer surface of the timing transmission device 35, is fixedly fixed by the bolt 41, and the oil tank ( A recoil starter 42 (see FIG. 2) is attached to the outer side of 40.

2 again, the other end of the crankshaft 13 opposite to the timing transmission device 35 also protrudes to the outer side of the crankcase 6, and at one end thereof, the flywheel 43 has a nut 44. It is fixedly mounted. The flywheel 43 not only serves as a cooling fan, but also has a plurality of cooling wings 45, 45... In addition, a plurality of attachment bosses 46 (one of which is shown in FIG. 2) are formed on the outer surface of the flywheel 43, and the centrifugal shoes 47 are swinged on each of the attachment bosses 46. Freely supported on the shaft. Since the centrifugal shoe 47 constitutes the centrifugal clutch 49 together with the clutch drum 48 fixedly mounted to the drive shaft 50 to be described later, if the rotation speed of the crankshaft 13 exceeds a predetermined value, the centrifugal shoe 47 The shoe 47 is pressed against the inner circumferential wall of the clutch drum 48 by its centrifugal force, so that the output torque of the crankshaft 13 can be transmitted to the drive shaft 50. The flywheel 43 has a larger diameter than the centrifugal clutch 49.

The engine cover 51 covering the engine main body 1 and the accessory mechanism includes a first cover half 51a on the flywheel 43 side and a second cover on the starter 42 side of the timing transmission device 35. It is divided into half bodies 51b, and is fixedly mounted to the engine body 1, respectively. A crankshaft-shaped bearing holder 58, which is coaxial with the crankshaft 13, is fixedly mounted to the first cover half 51a, and the bearing holder 58 is a bearing for rotating and driving the cutter C. 59 is provided via the air inlet 52 in the bearing holder 58 so that outside air can be introduced into the engine cover 51 as the cooling vanes 45, 45... Rotate. It is. In addition, a pedestal 54 covering the lower surface of the fuel tank 5 is fixed to the engine cover 51 and the bearing holder 58.

The second cover half body 51b defines a timing transmission chamber 92 for housing the timing transmission device 35 in cooperation with the timing transmission case 36. In the timing transmission case 36 and the second cover half body 51b, bosses 112 and 112 'contacting each other between the driving pulley 32 and the driven pulley 33 are integrally formed, and these bosses 112 and 112' are integrally formed. ) Is closed together with the engine body 1 by bolts 37. In this way, the timing transmission case 36 and the second cover half body 51b are coupled to each other and fixed to the engine main body 1 at the same time.

In addition, since the timing transmission device 35 for interlocking between the crankshaft 13 and the camshaft 26 is constructed in a dry manner and arranged outside the engine body 1, the sidewall of the engine body 1 has this apparatus. It is not necessary to particularly provide a seal for accommodating the 35, so that the engine body 1 can be made thinner and smaller, and the overall weight of the engine E can be significantly reduced.

In addition, since the timing transmission case 36 is interposed between the engine body 1 and the oil tank 40, the heat generated by the engine body 1 is blocked by the timing transmission case 36, and the oil tank 40 is disposed within the oil tank 40. Overheating of the storage oil O can be prevented.

In addition, since the timing transmission case 36 is indispensable to the OHC engine E, it does not cause the engine E to be enlarged.

In addition, since the timing transmission device 35 and the centrifugal shoe 47 of the centrifugal clutch 49 are connected to both ends of the crankshaft 13 with the cylinder block 7 interposed therebetween, The center of the engine E can be very close to the center of the crankshaft 13 so that the weight balance of the engine can be good, and the workability of the engine E can be improved while reducing the weight. In addition, since the load by the timing transmission device 35 and the drive shaft 50 acts on both ends of the crankshaft 13 during the operation of the engine E, the crankshaft 13 and the support thereof are supported. Concentration of the load on the bearings 14 and 14 'can be avoided and their durability can be improved.

In addition, between the engine body 1 and the centrifugal shoe 47, a flywheel 43 having a cooling blade 45 with a diameter larger than that of the centrifugal shoe 47 is fixed to the crankshaft 13, While avoiding large-sized engine E by the flywheel 43, the cylinder block is sucked by the air inlet 52 without being obstructed by the centrifugal clutch 49 by the rotation of the cooling blade 45. It can supply to the circumference | surroundings of 7 and the cylinder head 8 correctly, and can improve their cooling property.

In addition, since the oil tank 40 is attached to the engine body 1 adjacent to the outer side of the timing transmission device 35, the oil tank 40 can cover at least a part of the timing transmission device 35. This transmission apparatus 35 can be protected by cooperating with the 2nd cover half body 51b which covers the other part of the apparatus 35. FIG. In addition, the center of the engine E can be brought closer to the center of the crankshaft 13 by opposing arrangement between the oil tank 40 and the flywheel 43 with the engine main body 1 interposed therebetween.

As shown in Figs. 5, 14 and 15, an intake pipe 94 having the intake port 9 is integrally protruded from one side surface of the cylinder head 8, and this intake pipe 94 is provided. ), The vaporizer 2 is connected via an intake pipe 95 made of an elastic material such as rubber. One end of the intake pipe 95 is fitted to the outer circumference of the intake pipe 94, and a clamping ring 96 is fitted to the outer circumference thereof. The clamping ring 96 has a plurality of ring-shaped caulking grooves ( 96a) is formed. In this way, the intake pipe 95 is connected to the intake pipe 94. A flange 95a is formed at the other end of the intake pipe 95, and the support plate 97 and the insulator 98 made of a heat insulating material are disposed so as to sandwich the flange 95a. A head of a pair of connecting bolts 99 is welded to the support plate 97, and these connecting bolts 99 are insulated from the insulator 98, the vaporizer 2, and the case 4a of the air cleaner 4. ) The intake pipe 95 and the insulator 98 are inserted into the support plate 97 by being inserted into a series of bolt holes 100 penetrating the bottom wall, and screwing the nuts 101 at the ends thereof and tightening them firmly. ), A vaporizer 2 and an air cleaner 4 are attached.

The support plate 97 is integrally formed with a stay 97a extending upward. The stay 97a is fixed to the cylinder head 8 by a bolt 109.

Between the engine body 1 and the carburetor 2, a heat shield and a wind guide plate 102 are arranged. The heat shield and wind guide plate 102 is made of synthetic resin, and is integrally connected to one of the timing transmission case 36 made of synthetic resin, which is fixed to the engine body 1 with bolts 37, and the intake pipe 95 ) Has an opening 103 through which the bottom passes, and the lower end extends to the vicinity of the flywheel, that is, the cooling fan 43. In this way, the timing transmission case 36 and the heat shield and the wind guide plate 102 are configured as a part of a synthetic resin.

And, the heat shield and wind guide plate (102) blocks the radiant heat of the engine body (1) to prevent the heat effect on the vaporizer (2), and at the same time, the cooling air sent from the cooling fan (43) to the engine body (1), In particular, it guides the cylinder head 8 and contributes to effective cooling. In addition, since the heat shield and wind guide plate 102 is integrated with the timing transmission case 36 fixed to the engine main body 1 and is made of a part of a synthetic resin, the heat shield and wind guide plate 102 is a timing transmission. By being supported by the case 36, it is possible to omit the bolts for fixing the heat shield and the wind guide plate 102 itself to the engine main body 1 as shown in the example, or to significantly reduce the number of bolts used. As a result, the timing transmission case 36 and the heat shield and the wind guide plate 102 are integrated, and the number of parts assembling processes can be reduced, and the cost can be greatly reduced.

Next, the lubrication system of the engine E will be described with reference to FIGS. 3, 13, and 16 to 18F.

As shown in FIG. 3, one end of the crankshaft 13 is disposed to penetrate the oil tank 40 while being in close contact with the oil seals 39 and 39 ′ mounted on both side walls of the oil tank 40. The crankshaft 13 has a through hole 55 communicating between the inside of the oil tank 40 and the crank chamber 6a. The lubricating oil (0) is stored in the oil tank (40), and the amount of storage is always the oil (0) at any driver's attitude of the engine (E). It is set to expose on the face of.

The outer wall of the oil tank 40 is formed with a bowl-shaped portion 40a recessed in the tank 40 about the crankshaft 13. In this oil tank 40, an oil slinger 56 is attached to the crankshaft 13 so as to be fixed to the crankshaft 13 with a nut 57. The oil slinger 56 has two plates 56a and 56b extending radially opposite from each other at the center portion fitted to the crankshaft 13, while the plate 56a has an engine body 1 at the middle portion thereof. ), The other plate 56b is bent along the curved surface of the bowl-shaped portion 40a at the middle portion, and when the oil slinger 56 is rotated by the crankshaft 13, the engine E In at least one of the two plates 56a and 56b, the oil 0 in the oil tank 40 is scattered to generate any oil spray.

In particular, by forming the bowl portion 40a on the outer wall of the oil tank 40, the dead space of the oil tank 40 can be reduced, and the engine having the bowl portion 40a faced downward ( Even in the horizontal posture of E), the oil which exists around the bowl-shaped part 40a can be stirred and scattered with the board 56b. This means that it is possible to reduce the amount of reactive storage of oil O in the oil tank 40 while ensuring the production of efficient oil spraying.

Moreover, the said oil seal 39 which adjoins the outer peripheral surface of the crankshaft 13 penetrating this is attached to the center part of the bowl-shaped part 40a, and the tip of the crankshaft 13 is provided in the bowl-shaped part 40a. A driven member 84 is disposed to be driven in accordance with the recoil starter 42 fixedly mounted to the recoil starter 42.

In this way, the space in the bowl-shaped portion 40a is effectively used for the arrangement of the driven member 84, and the proximity of the recoil starter 42 to the oil tank 40 becomes possible, and the engine E It can contribute to the miniaturization of the whole.

3, 12 and 17, the crank chamber 6a is connected to the actuation valve cam chamber 21 via the oil transfer conduit 60, and the oil transfer conduit 60 is connected to the crank chamber 6a. A one-way valve 61 for allowing only one direction of flow to the actuating valve cam chamber 21 is mounted therebetween. The oil transfer conduit 60 is integrally formed in the timing transmission case 36 along one edge thereof, and the lower end of the oil transfer conduit 60 is formed in the valve chamber 62. The timing transmission case 36 is integrally formed with an inlet tube 63 protruding from the valve chamber 62 to the rear of the timing transmission case 36 so that the inlet tube 63 communicates with the crank chamber 6a. And the sealing member 65 is inserted through the connection hole 64 in the lower part of the crankcase 6. The valve chamber 62 is provided with the one-way valve 61 arranged to allow flow in one direction from the inlet pipe 63 to the valve chamber 62. This one-way valve 61 is a lead valve in the example of illustration.

In addition, the timing transmission case 36 is integrally formed with an outlet tube 66 protruding from the upper end of the oil transfer conduit 60 to the rear of the timing transmission case 36, and the outlet tube 66 has an operation valve chamber. It fits in the connection hole 67 of the cylinder head 8 side part so that it may communicate with (21).

The head cover 71 is constituted by friction welding the cover outer plate 105 made of synthetic resin having the flange portion 71a and the cover inner plate 106 made of synthetic resin having the fitting wall portion 71b to each other. . These cover outer and inner plates 105 and 106 are formed so as to partition the suction chamber 74 therebetween.

The suction chamber 74 formed a flat shape along the upper surface of the actuating valve cam chamber 21, and four orifices 73, 73 ... are laid on the bottom wall, that is, the four corners of the inner plate 105. Further, the bottom wall has two long and short suction pipes 75 and 76 integrally protruding in the actuating valve cam chamber 21 side by side at intervals orthogonal to the axis of the camshaft 26 at the center thereof. Orifices 73 and 73 are provided in these.

As shown in FIG. 12, FIG. 13, and FIG. 17, the suction chamber 74 communicates with the inside of the oil tank 40 via the oil return conduit 78 on the other side. The oil return conduit 78 is integrally formed in the timing transmission case 36 along the other edge opposite to the oil transfer conduit 60. The timing transmission case 36 is integrally formed with an inlet tube 78 protruding from the upper end of the oil return conduit 78 to the rear of the timing transmission case 36, and the inlet tube 78 is a suction chamber ( It is connected to the outlet pipe 80 formed in the head cover 71 via the connector 81 so that it may communicate with 74.

In addition, the timing transmission case 36 is integrally formed with an outlet tube 82 protruding from the lower end of the oil return conduit 78 to the rear of the timing transmission case 36, and the outlet tube 82 is an oil tank. It fits in the return hole 83 provided in the oil tank 40 so that it may communicate in 40. The opening end of the return hole 83 is disposed near the central part in the oil tank 40 so as to be exposed on the liquid level of the oil in the oil tank 40 at any driver's attitude of the engine E. FIG.

As shown in FIG. 4, the breather passage 68 is provided in the camshaft 26. The breather passage 68 is opened toward the operation valve cam chamber 21 at the axial middle portion of the camshaft 26. A short horizontal hole 68a serving as an inlet and a long vertical hole 68b communicating with the horizontal hole 68a and opening in the end face of the bearing cap 30 through the center of the camshaft 26 are provided. have. The bearing cap 30 has an enlarged breather chamber 69 in communication with the outlet of the longitudinal hole 68b, and a pipe connecting tube 107 communicating with the breather chamber 69 and protruding on the outer surface of the bearing cap 30. Is formed, and the breather chamber 69 communicates with the air cleaner 4 via the breather pipe 70 connected to the pipe connecting pipe 107.

The ball bearing 27 ′ supported by the bearing cap 30 is composed of a seal paste provided with a seal member 108 on the side facing the breather chamber 69. Therefore, the oil spray in the actuating valve chamber 21 can lubricate the ball bearing 27 ', but cannot reach the breather chamber 69 through the ball bearing 27'.

Then, during operation of the engine E, when the oil slinger 56 scatters the lubricating oil 0 in the oil tank 40 by the rotation of the crankshaft 13 and generates oil spray, the piston 15 When the crank chamber 6a is depressurized by the upward movement, this oil spray is sucked into the crank chamber 6a through the through hole 55, and lubricates the crank shaft 13 and the piston 15 around. Next, when the crank chamber 6a is boosted by the downward movement of the piston 15, the oil spray is opened by the opening of the one-way valve 61 together with the blow-by gas generated in the crank chamber 6a. ) Is supplied to the operating valve cam chamber 21 to lubricate the camshaft 26, rocker arms 24, 25, and the like.

When oil spray and blow-by gas in the actuating valve cam chamber 21 flow into the cross hole 68a of the breather passage 68 of the camshaft 26 during rotation, the centrifugal force is applied in the rotating cross hole 68a. The gas-liquid is separated, and the oil component is returned to the actuating valve cam chamber 21, and the blow-by gas flows through the vertical hole 68b, the breather chamber 69, and the breather pipe at the cross hole 68a of the breather passage 68. The engine E is sucked in via the 70 and the air cleaner 4 sequentially.

As described above, the pipe connecting pipe 107 connecting the breather chamber 69 and the breather pipe 70 supports a bearing cap 30 that supports a ball bearing 27 'for supporting the camshaft 26. Since it is formed in the bearing cap 30, the bearing cap 30 also serves as a gas returning member for blowing blow-by gas into the breather pipe, and the structure can be simplified and the number of parts can be reduced.

However, since the actuating valve cam chamber 21 communicates with the air cleaner 4 via the breather passage 68, the breather chamber 69, and the breather pipe 70 as described above, the actuating valve cam chamber 21 The pressure is maintained at atmospheric pressure or slightly below it.

On the other hand, the crank chamber 6a discharges only the positive pressure component of the pressure pulsation from the one-way valve 61, so that the crank chamber 6a is in a negative pressure state on the average, and the negative pressure is supplied to the oil tank 40 via the through-hole 55. Since it is transmitted to the suction chamber 74 via the oil return conduit 78, the suction chamber 74 has a lower pressure than the actuating valve cam chamber 21, and the suction chamber 74 in the oil tank 40. The pressure is lower than). As a result, the pressure is transferred from the actuating valve cam chamber 21 to the suction chamber 74 through the suction pipes 75 and 76 and the orifices 73, 73 ... and through the oil return conduit 78. Since it also occurs in the tank 40, the oil spray in the actuating valve cam chamber 21 or the liquefied and condensed oil in the actuating valve cam chamber 21 is accompanied by the suction pipes 75 and 76 and the orifices 73 and 73. Through the suction chamber 74, and descends the oil return conduit 78 to reflux to the oil tank 40.

At that time, as described above, four orifices 73, 73 ... are laid on the corners of the bottom wall of the suction chamber 74, and protrude into the actuating valve cam chamber 21 from the center of the bottom wall, thereby providing a camshaft. Orifices 73 and 73 are provided in two long and short suction pipes 75 and 76 side by side at intervals orthogonal to the axis of (26), so as shown in FIG. 18, the engine E The upright state (A) is, of course, the state inclined in the left direction (B), the state inclined in the right direction (C), the rotation state in the left direction (D), the rotation state in the right direction (E), inverted Any of the six orifices 73, 73 ... is immersed in the oil accumulated in the actuating valve cam chamber 21 at any driver posture, such as in the state (F), so that the oil is sucked up in the chamber 74. I can suck it up.

Next, a second embodiment of the present invention shown in Figs. 19 and 20 will be described.

To the timing transmission case 36 accommodating the timing transmission device 35, a case cover 36 ′ made of synthetic resin covering the outer surface of the timing transmission device 35 is engaged. In the timing transmission case 36 and the case cover 36 ', bosses 112 and 112' which come into contact with each other between the driving pulley 32 and the driven pulley 33 are integrally formed, and these bosses 112 and 112 'are integrally formed. ) Is closed together with the engine body 1 by bolts 37. In this way, the timing transmission case 36 and the case cover 36 ′ are coupled to each other and fixed to the engine main body 1.

The case cover 36 ′ is provided with a circular oil tank 40 connected to the crankshaft 13. The oil tank 40 is also made of synthetic resin, and is formed integrally with the case cover 36 ', and has an inner tank half 40a which shares a part W of the side wall with the case cover 36', It is comprised as the outer tank half body 40b which sandwiches the sealing member 89, such as an O-ring, on the outer periphery of this inner tank half body 40a, and both tank half bodies 40a and 40b protrude in the peripheral part of them. The bolts 41 are coupled to each other in the plurality of connecting bosses 93 and 93 '. The oil supply port 116 which is normally closed by the screw cap 115 is provided in the outer side wall of the outer tank half body 40b.

Other configurations are the same as those of the first embodiment, and the same reference numerals are given to the parts corresponding to the first embodiment in Figs. 19 and 20, and the description thereof is omitted.

In this way, the oil atomized in the oil tank 40 uses the pressure pulsation of the crank chamber 6a and the function of the one-way valve 61, and the crank chamber 6a of the OHC type 4 cycle engine E is used. And the operating valve cam chamber 21 and reflux it to the oil tank 40, the engine interior can be reliably lubricated by oil spraying at any operating position of the engine E. The dedicated oil pump is unnecessary because of the circulation of the spray, and the structure can be simplified.

In addition, not only the oil tank 40 made of synthetic resin, but also the oil transfer conduit 60 between the crank chamber 6a and the operation valve cam chamber 21, and between the suction chamber 74 and the oil tank 40 Since the connecting oil return conduit 78 is provided outside the engine main body 1, there is no interference in the thinning and downsizing of the engine main body 1, and can contribute greatly to the weight reduction of the engine E. As shown in FIG. In particular, since the oil transfer conduit 60 and the oil return conduit 78 of the external arrangement are less likely to be affected by the heat in the engine body 1, overheating of the lubricating oil 0 can be avoided. In addition, by integrating the oil transfer conduit 60, the oil return conduit 78, and the timing transmission case 36, it is possible to contribute to the reduction of the number of parts and the improvement of the assembly.

In the second embodiment, the timing transmission case 36 is interposed between the engine body 1 and the oil tank 40, and the inner tank half 40a of the oil tank 40 has a case cover ( 36 ') is integrally molded and shares a portion W of the side wall, so that the heat generated from the engine body 1 is blocked by the timing transmission case 36, and the storage oil O in the oil tank 40 is blocked. In addition to preventing overheating, the oil tank 40 and the case cover 36 'can be integrated, thereby simplifying the structure and further reducing the cost.

This invention is not limited to the said Example, A various design change is possible without deviating from the range of the summary.

Claims (6)

An oil tank 40 is attached to one side of the engine main body 1, and the oil tank 40 has a four-cycle engine containing an oil slinger 56 that scatters storage oil O and generates oil spray for lubrication. To Timing for accommodating the timing transmission device 35 which connects between the crankshaft 13 and the camshaft 26 supported by the engine main body 1 between the engine main body 1 and the oil tank 40. The four-cycle engine, characterized in that fitted between the transmission case 36. A case cover (36 ') covering the outer surface of the timing transmission device (35) is coupled to the timing transmission case (36), and this and the side wall (W) are attached to the case cover (36'). 4 cycle engine, characterized in that the connection to install the oil tank (40) to share. The bowl-shaped portion according to claim 1 or 2, wherein a bowl-shaped portion 40a is formed on the outer wall of the oil tank 40 with the crank shaft 13 recessed in the tank inner direction. And the oil slinger (56) to follow the convex curved surface of (40a). The recoil starter 42 is disposed adjacent to the outer side of the oil tank 40, and the driven member 84 driven by the recoil starter 42 is connected to the bowl-shaped portion 40a. A four cycle engine characterized in that the outer end of the crankshaft (13) penetrating is fixed in the bowl portion (40a). The heat exchanger is provided between the engine main body 1 and the carburetor 2 connected to the engine main body 1, and is attached to the crankshaft 13. The heat shield and the wind guide plate 102 for guiding the cooling wind from the cooling fan 43 are arranged, and the heat shield and the wind guide plate 102 are integrally connected to the timing transmission case 36, The four-cycle engine, characterized in that the timing transmission case 36 and the heat shield and wind guide plate (102) consisting of a part. The oil transfer conduit (60) and oil for carrying out oil spraying between the oil tank (40) and the part to be lubricated in the engine body (1) are provided in the timing transmission case (36). A four cycle engine, characterized in that to form a return conduit (78).